PTFE Fiber
PTFE (polytetrafluoroethylene, Teflon®) is the ultimate chemical survivor among organic fibers — a fully fluorinated carbon chain (—CF₂—CF₂—)ₙ where the carbon-fluorine bond is one of the strongest in organic chemistry. The result is a fiber that is essentially chemically inert: it resists everything except molten alkali metals and elemental fluorine at extreme conditions. PTFE cannot be melt-spun (it decomposes before melting) — instead it is produced by emulsion spinning, where a PTFE dispersion in a sacrificial matrix (viscose or PVA) is spun, sintered at ~380°C to fuse the PTFE particles, and the matrix burned off. Alternatively, paste extrusion followed by stretching produces expanded PTFE (ePTFE), the microporous membrane behind Gore-Tex® waterproof-breathable technology. Its continuous service temperature of 260°C is the highest among organic fibers. Its Achilles heels are low strength (1.5–2.5 cN/dtex), significant creep under load, and the highest density among organic HPFs (2.1–2.3 g/cm³).
High-Performance / Polytetrafluoroethylene (Teflon® Fiber)
Quick Facts
| Type | Fluoropolymer fiber; the most chemically inert organic material known; (—CF₂—CF₂—)n |
| Production | PTFE cannot be melt-spun (decomposes before melting); produced by emulsion spinning (PTFE dispersion in viscose or PVA matrix → sintered → matrix burned off) or paste extrusion + stretching → expanded PTFE (ePTFE/Gore-Tex® membrane) |
| Service temperature | Continuous: 260°C; short-term: 290°C — the highest continuous-use temperature of any organic fiber |
| Chemical resistance | Essentially universal; attacked only by molten alkali metals and elemental fluorine at high temperature/pressure |
| Friction coefficient | 0.02–0.10 — lowest of any solid material; self-lubricating |
| Density | 2.1–2.3 g/cm³ — heavy for an organic fiber (PET: 1.38) |
Properties
| Property | Rating | Engineering implication |
|---|---|---|
| Chemical inertness | ★★★★★ | Resists everything; the universal chemical barrier; zero moisture absorption; zero chemical attack |
| Thermal stability | ★★★★★ | 260°C continuous; highest among organic fibers; no melting (decomposes at ~327°C) |
| Friction / non-stick | ★★★★★ | Lowest coefficient of friction of any solid; self-lubricating; nothing sticks to it — both an advantage and a processing challenge |
| Strength | ★★☆☆☆ | Low; 1.5–2.5 cN/dtex; not a load-bearing fiber; strength is not why PTFE is chosen |
| Creep | ★★☆☆☆ | Significant cold flow under load; limits use in sustained-tension applications |
| Cost | ★★★★☆ | Expensive; specialty material; justified only by chemical/thermal resistance requirements |
Applications
| Application | Form | Key criteria |
|---|---|---|
| Hot corrosive gas filtration | PTFE needled felt; membrane-laminated | Coal power, cement, waste incineration; 260°C continuous; universal chemical resistance |
| Pump packing / gland seals | PTFE braided packing; with graphite or aramid corners | Chemical pumps, valves; self-lubricating; universal chemical compatibility |
| Space / aerospace | PTFE woven fabric; thermal blankets | Extreme thermal and chemical environment; non-flammable; zero outgassing |
| Membrane (ePTFE / Gore-Tex®) | Expanded PTFE membrane; laminated to fabric | Waterproof (pores < water droplet) + breathable (pores > water vapor); the original waterproof/breathable technology |
Summary
PTFE is the ultimate chemical survivor — nothing attacks it, and it operates continuously at 260°C. It is chosen when the environment destroys everything else, not for its mechanical properties. See the Textile Material framework.